Method for the production of dentures



july?, 1931. W. s'. RICE n,s13,5s3

METHOD FOR THE PRODUCTION 0FV DENTURES Filed May 28, 1928 E u QW?? ///4.

/ f@ 5&6

/M/ENTOR' l Patented '.uly 7, 193i PATENT oFFI'cE -WILLIAJJILVS. "RICE,F WASHNGTON, DISTRICT OF COLUMBIA.v

METHOD Fon THE PRODUCTION or nnNTtrnns Application inea May 28,1928.serial No. 281,278.

(GRANTED UNDER THE AcToE MARCH a, 1883,`As AMENDED APRIL so, 192s; 37oo. e. 757) This invention described herein may -be manufactured and usedby orfor the Government for governmental purposes, without the vestedand the denture, which replaces it, vul-` canized or otherwise treatedand thus by the elimination of expansion and warping, pro- !zo ducing aden-ture which will conform to the contour of the gums and hard palateto the minutest details.

v Another object of this invention is to provide means. for embeddingthe teeth in metal in the investment flask thus holding themsolidly inposition for packing and vulcanization, curing or otherwise hardeningthe base plate material.

Other objects of this invention are to materially 'lessen both time andlabor in the production of `dentures and otherl restorative forms byeffecting a reduction in the amount 4of grinding and polishing necessaryfor fini.shing and to provide metallic separating layers between theupper and lower sections of the flask. With these and other objects inviewthis invention consists in certain novel details of construction,combination and arrangement of' parts to be more set forth and claimed.f

Brieflystated, this invention consists in an improved method forproducing models, dentures, inlays, etc., lby the use of metallicallysurfaced models or metallically lined molds between the hard smoothsurfaces of which the plastic mbdel is invested and the plastic denturevulcanized or cured to form the 1inished denture or other artificialrestoration.

Referring' more particularly to the accomparticularly hereinafter`panying drawings in which corresponding parts are indicated by similarreference L 'characters F igl. 1 is a sectionized isometric'view of animpression tray with wax or plaster impression contained therein.

Fig. 2 is a sectionized isometric view of an impression tray andimpression material contained therein, the impressionV cavity beingcoated with a metallic lining.

Fig. 3 is a partially sectionized elevation of an upper and lower fulldenture mounted on an articulator. v

Fig. 4 is a partially sectionized perspective View of upper model shownin Fig. 3, mounted in the lower section of (an investment flask.

Fig.' 5 is a partially sectionized perspective -view showing the uppermold coated with metal and mounted in the investment flask.

Fig. 6 -is a sectionized elevation showing the upper model invested in aclosed flask for vulcanizing, curing, molding or casting. y

The customaryl method of making vulcanite dentures involves theparamount features toy wit: taking the impression, pouring the plasntercasts, mounting casts on the articulator, `building the wax models,investing, packing L. i

and then vulcanizing.

In the usual meth od the plaster cast is made by pouringplaster-directly into the limpression'. This givesa plaster model, orcast of the patients gums on which the wax model denture is built. Thismodel denture is nvested entirely in plaster, immersed in warm Water andafterthe evacuation of the Wax, rubber is packed in the plaster mold andvuli canized.

The porosity of the plaster causes adhesion of the vulcanite andthe'compressibility of the ,plaster and uneven expansion thereofl.causes expansionand warping of the denture.

The result is rough vulcanite dentures which do not' follow the exactcontour of the patients gums and hard palate, and which requireconsiderable grinding and polishing to, approximate a fit and to makethe exterior of the denture resemble in smoothness the gums.

yIt is therefore the aim and purpose of this invent-ionto provide amethod to eliminateI the deleterious results caused by investing the Itwill be noted that for the sake of brevity and clearness the materialswhich are used most commonly in prosthetic dentistry are( referred tothroughout the following description, namely, wax for the constructionof the base plate of the model, plaster for the molds, and rubber forvulcanization in the production of the finished denture or otherrestorative part. However, it is to be understood that in theapplication of my process it is not necessary to adhere to thesematerials as any suitable substitutes may replace them with not onlyequal, but in some cases, superior results.

For example, bakelite may be used instead of rubber, cement instead ofplaster, etc. IVhcn bakelite is used for dentures, plaster cannot beused for molds in the ordinary dental processes, since it would bedetrimental to the finished product to permit contact of surfaces ofbakelite against those of plaster. In my improved process plaster moldsmay be used for bakelite dentures as there is an intervening layer ofmetal between the plaster and the bakelite.

In 'the illustrated embodiment characterizing this invention, thenumeral (1) Fig. l represents an impression tray and (2) the impressionmaterial, either wax, composition or plaster. The valley or groove (3)represents the impression made therein by the gums of an edentulouspatient.

In Fig. 2 is shown the impression tray,

impression material and impression as shown in Fig. l, but it will benoted that covering lthe entire surface uf the impression is a metalliccoating or. layer (4) This metallic layer \(4) has been sprayed onto thesurface by a metallic air brush similarv to those used in blowing minuteparticles of metal on the hulls of vessels until a. protective coatingof sufficient thickness is deposited.

The metal as it is blown on adheres to either the hull or to the surfacealready laid down and the thickness of the metallic layer is determinedby the period of the operation and the character of spray. Preparatoryto spraying the impression surface a suitable separator may be applied,then after a metallic layer of suflicient thickness has been deposited,said impression surface with its metal coating is covered with plasterand the latter built up to provide the requisite base (5). I/Vhen theplaster has hardened to the desired extent and become aiixed to themetallic coating, the impression material (2) is removed and themetallically coated cast is now ready for mounting on the articulator.

A complementary cast for the lower jaw having a plaster base (5') and asabove outlined, a metallic coating (4') is built, and with the aid of abite plate (not shown) both are mounted in their proper relativepositions on an articulator (6) as clearly shown in Fig. 3 of thedrawings.

Upon these upper and lower metallically covered casts are developed thewax dentures (7) and (7 by the ordinary process of first laying a baseplate then building up the ridge and finally placing the teeth (18) inposition. At the completion of the attachment of the teeth and after theusual adjustments for occlusion and articulation have been made themodels are removed from the articulator and placed in the fiask.

In the asking operation, the models embodying the cast with its metalliccoating, plaster base (5) and wax denture (7) are placed in the lowersection (8) of investment as defined the entire surface (11) of theplas` ter and of the wax model denture (7) including the teeth (18) maybe covered with a thin application of a separator and coated with ametallic layer The upper section 14) of the investment flask (9) isplaced on top of the lower section (8) as shown in Fig. 5, and filledwith plaster, after which the flask is closed and immersed in warmwater. On completion of investment and elimination of the wax thesections are separated, the molds may be coated with a separator andpacked with dental rubber, whereupon the flask is again closed andplaced in the vulcanizer.

After vulcanization, the denture is removed from the flask, ground andpolished in the usual manner, but since the vulcanization of the rubberhas taken place between hard smooth metallic surfaces, grinding andpolishing is necessary only to remove the ridges which mightpbe formedat the line union of the flask surfaces, or small sections of metaladhering to the surface of the denture. A

For making partial plates the same procedure is followed as in the caseof full plates. For single plates, or single partial plates and bridgework the occluding model may be metallically coated. This provides amore solid occluding surface for manipulation on the articulator.

For inlay work an impression of the preparedcavi-ty and either a portionof the tooth which is immediately adjacent the cavity, or the wholetooth isObtained. This impression is then coated or lled with metal, asprevi- -ously described, until thecoating is of sufii-4 cient thicknessto be removed from the impression or mold without breaking.

If desired the cast which is made inthis Way may be backed with aplaster base as When making plate casts. This cast is an eX- act modelof the tooth or that portion of the tooth containing the cavity. With amodel of this sort the dentist has an exact metallic representation ofthe patients tooth to Work'on in the laboratory, ,which manifestlyfacilitates handling in the subsequent laboratory operations. f

In inlay work the wax model o`f the .cavity may be coated entirely withmetal except for `thesmall opening for the pin' which provides for asprue hole. -The metallic cast thus formed may be invested.

. In making castings for inlay Work, metallic base plates, bridge Work,etc., the plastic model may be entirelyv coated with metal except Whereit is necessaryv for feed and vent sprues. The metal used for thispurpose Will necessarily be one having a high melting point. A castthusformed may then be filled with molten metal in the usual manner,that is, by either centrifugal vforce or by creation of a vacuum' at thevent sprues.

Dies and counter-dies for sWaging metallic base plates may beconstructed by spraying an appropriate metal l on the impression andmodel and either building up the dies or counter-dies'by continuing thespraying procon the metallically lined molds. Which are'I used, and theease With Which they are built.

ess or by mounting the surfaces on metallic or'other suitable bases.

In conclusion it will be noted that the superiority of my improved4method is dependent Tin, which `at present seems to be-the mostdesirable metal, is extremely inexpensive, and any lslight eXtra costlwhich might be in- -curred in the use of this m'ethod is however amplyoffset by the reduction bethtime and labor" incidental to rinding andpolishing for `finishing the den ure.

` Although in the foregoingcertain elements have been described as bestadapted to perform the functions allotted? them, nevertheless it isto`be understood that various ini-nor changes mayT be resorted to withinthe scope ,of the appended claims Without departing from or -sacrificingany of the princlples of f I-Iaving described my invention, what I claimas new and Wish to secure by Letters Patent is: l 1. "Aprocess forproducing artificial restorations of the oral cavity, consistinginproducing a metal surfaced cast, developing a model upon said cast,metallizing the exterior surface of the model, embeddingcthe modelandcastinacementitioussubstance,evacuatingthe modelling material to providea cavity Whose .internaldimensions conform to the dimensionalrequirements of the desired restoration and perfecting the latter withinsaid cavity.

2. A process for producing artificial restorations of the oral cavity,consisting in promensions conform to the dimensional re" quirements ofthe desired restoration and then perfecting said restoration Within thecavity.

3. A process for producing artificial restorations of the oralcavity,consisting in forming a model With metallized exterior and interiorsurfaces, embedding the metal in a cementitious substance, evacuatingthe modelling material to define arnet-al Walled cavity in thecementitious substance, the internal dimensions of Which'conform to thedimensional requirements ofthe desired restoration and completing saidrestoration Within said cavity. 4. A process for producing artificialrestorations of the oral cavity, consisting in forming a model withmetallized exterior and interior surfaces, embedding the model in acementitious substance, evacuating the modelling material to define ametal Walled cav- ,ity the diinensions of -Which conform to thedimensional requirements of the finished restoration, filling saidcavity with a restoration producing material and subjectin the latter tothe temperature requisite to t e finished product. t

5. A process for producing artificial restorations of the oral cavity,consisting in forming a Wax model denture with metallized exteriorandinterior surfaces, embedding the model denture in' a cementitioiissubstance, evacuating the Wax modelling material .to produce a metalWalled cavity having the dimensiona equirements of the finishedrestoration' and filling the cavity With a restoration producingmaterial and then subjecting the latter `to temperatures 4requisite tothe finish-ed product.

6. A process for producing artificial res- .torationsof the oral cavity,'consisting in metal spraying'an impression surface, forming la modelcast therefrom, developing a model upon the: cast,l metal spraying themodel surface upon the exterior surface, embedding the model and cast ina cementitious substance, effecting evacuation of the model- .lingmaterial to produce a metal Walled cavity, the dimensionsof Whichcorrespond `to those of the finished restoration and perfecting saidrestoration Within said cavit p i 7. A process for producing-artificlaltrestorations ofthe oral cavity, consisting inr "15 metallic shellconforming to the lingual side Wax model denture upon the cast, metaldesired artificial denture, filling the said spraying the exteriorsurface of the model matrix With suitable denture material, and denture,embedding said denture in a cehardening the material to form thefinished mentitious substance, effecting evacuation denture.

5 of the Wax modelling material to produce a WILLIAM S. RICE. 70

metal Walled cavity, the dimensions of which correspond to those of thefinished restoration and then completing Vsaid restoration Within thecavity. c

8. A process for producing artificial resto- 'v rations of the oralcavity, consisting in metal spraying an impression surface previouslyformed in molding material, treating'said metallized surface with aplastic substance,

removing the molding material to provide a 90 metal cast, developing aWax model denture upon the cast, spraying a metal surface upon theexterior of the model denture, effecting evacuation of the Wax of thedenture to produce a metal Walled cavity, the dimensions 85 of whichcorrespond to those of the finished restoration and perfecting saidrestoration Within said cavity.

9. A process for producing artificial restorations of the oral cavity,consisting in V 0 forming an impression surface in modelling material,imparting a metal surface to the first mentioned surface, transferringthe metal surface to a cementitious substance, re-

moving the molding material to provide a 95 metal cast, developing a Waxmodel denture upon the cast, metallizing the exterior of the denture,embedding the denture in a cementitious substance, effecting evacuationof the Wax material of the model denture to provide 100 a metal Wallcavity the dimensions of which correspond to those of the finishedrestoration forming material and subjecting such material totemperatures requisite to obtaining the finished restoration.

10. The method of producing an artificial denture involving theproduction of a metal Wall Which method comprises forming a trialdenture with teeth in place, forming a rigid 110 of the trial dentureand teeth, forming a mold including the shell as a Wall thereof,

v removing the trial denture leaving the teeth and shell in place,filling the mold with suitable denture material, and hardening thematerial to form the finished denture.

11. The method of producing an artificial denture involving theproduction of a metal mold which method comprises making a rigid 100metallic shell conforming exactly t0 the surk face of the mouth, forminga trial denture With teeth in place, forming a rigid metallic shellconforming to the lingual side of the 4 trial denture and incasing saidteeth, remov- 125 ing the trial denture leaving the teeth rigidly heldby the latter shell, placing the two shells together in matrix formingrelation to pro-A videa cavity 'Whose internal dimensions conf il formto the dimensional requirements of the

